The ageing of the low-frequency water disturbances caused by swimming goldfish and its possible relevance to prey detection.

摘要: Wakes caused by swimming goldfish (Carassius auratus) were measured with a particle image velocimetry system and analyzed using cross-correlation technique. Particle velocities in horizontal plane (size of measuring 24 cmx32 cm or 20 cmx27 cm) determined, the vorticity was derived from these data. The wake behind can show clear vortex structure for at least 30 s. significantly higher than background noise could still be detected 3 min after fish (body length 10 had passed through plane. Within this time span, lateral spread fish-generated wakes exceed 6 fish. Measurements man-made open-air pond showed that water quasi-natural environment as small 1 mm s(−)(1). Background did not s(−)(1) long no moving animal present possible advantage piscivorous predators being able to detect analyze is discussed.